The goal of the Laboratory CORE is to provide high purity eosinophil preparations and to assess cell function when placed in the different environments of Projects 1-4. It will be the tasks of this facility to: 1. Provide highly pure peripheral blood eosinophils and lymphocytes from normal and allergic asthma subjects and pure BAL eosinophils from allergic asthma subjects following SBP-Ag. 2. Perform functional assessment of human eosinophil biology, 3. Adapt current protocols to the requirements of each project,